This invention relates to a compressor blade with reduced aerodynamic blade excitation, in particular for the fan of aircraft engines.
Compressor blades with a large chord length used on certain types of aircraft-engine compressors are loaded to such an extent under certain operating conditions that damage to or life reduction of the compressor blade and the compressor disk may occur.
In order to reduce the stressing of the compressor blades, the assignee of the present application has previously filed a U.S. patent application on Apr. 5, 2004, to Erik Johann, entitled “COMPRESSOR FOR AN AIRCRAFT ENGINE”, in which it was disclosed to provide a flow transition fixation means in the form of a surface roughness applied to the suction side of the blade at a certain distance from and parallel to the blade leading edge and clearly ahead of the area of the compression shocks acting upon the blade. The local fixation of the transition area away from the compression shock area suppresses, or at least limits, coupling of the interrelated oscillation in the transition and compression shock area and, ultimately, avoids oscillation of the compression shocks or limits them to such an extent that their vibration-augmenting reaction on the natural vibrations of the compressor blade occurring under certain flight conditions, which eventually may lead to damage of the compressor blades and the compressor disk, is prevented.